Self-cooling beverage container having a heat exchange unit using liquid carbon dioxide and a twist top activation system

ABSTRACT

A self-cooling container for holding a food or beverage which includes a heat exchange unit (HEU) secured internally thereof so that the food or beverage is in contact with the outer surface of the HEU, the HEU being closed by a frangible membrane which is punctured by a pierce pin when a twist base activator is rotated in a first direction to create dis-equilibrium to cause liquid carbon dioxide contained within the HEU to pass directly from the liquid to the gaseous state and pass through a restricted orifice to atmosphere to cool the food or beverage.

FIELD OF THE INVENTION

The present invention relates generally to containers for holding food or beverage in which there is also included a heat exchange unit using liquid carbon dioxide and having an outer surface which contacts the food or beverage and which when activated alters the temperature of the food or beverage.

It has long been desirable to provide a simple, effective and safe device which may be housed within a container such as a food or beverage container for the purpose of altering the temperature of the food or beverage on demand.

In many instances, such as where one is in locations where ice or refrigeration are not readily available such as camping, at the beach, boating, fishing or the like it is desirable to have beverages which can be cooled before consumption. In the past it has been necessary that the individual take an ice chest or the like which contains ice and the containers for the beverages so that they can be cooled and then consumed in the manner desired. The utilization of such ice chests is cumbersome, takes up a substantial amount of space and lasts for only a very limited time after which the ice must be replaced. While in use it is also necessary that the water resulting from the melted ice be drained from the ice chest from time to time.

As a result of the foregoing, there have been numerous instances of attempts to provide a container housing a food or beverage and also housing therein a heat exchange unit which when activated would cool the food or beverage contained therein. The heat exchange units in such prior art devices housed a refrigerant material usually under pressure which when released would absorb the heat in the surrounding food or beverage thereby cooling the same prior to consumption. The refrigerants utilized in the heat exchange units of the prior art included gases under pressure such as hydrofluorocarbons, ammonia, liquid nitrogen, carbon dioxide, and liquid carbon dioxide. There has also been developed a system using compacted carbon particles which adsorb carbon dioxide gas under pressure. When the heat exchange unit is exposed to the atmosphere by opening a valve, the carbon dioxide gas desorbs and cools the food or beverage in the container. Examples of such systems are shown in U.S. Pat. Nos. 7,185,511, 6,125,649 and 5,692,381. Examples of such prior art patents including carbon dioxide in its gas or liquid form is shown by U.S. Pat. Nos. 3,373,581; 4,688,395; and 4,669,273. The containers utilizing such heat exchange units as illustrated in the prior art are complex and difficult to manufacturer, thus causing great expense, rendering such prior art self-chilling beverage containers commercially unattractive. In addition, where liquid carbon dioxide was utilized, the release of the liquid carbon dioxide resulted in the liquid carbon dioxide transitioning into the solid state which provided only limited reduction in temperature of the food or beverage.

Applicant has discovered that by charging the heat exchange unit in such containers with liquid carbon dioxide and then discharging the carbon dioxide through a properly sized restricted orifice, the liquid carbon dioxide passes directly from the liquid to the gaseous state. Such a system was disclosed in PCT/US2015/028318 which is incorporated herein. The system disclosed therein utilized machined metal parts to develop the restricted orifice. As a result, Applicant developed a system utilizing a dual function molded plastic valve to develop the restricted orifice and such is disclosed in PCT/US16/23194 which is incorporated herein. This system was activated utilizing a push button to move the valve into position to cause the liquid carbon dioxide to transition to the gaseous state and exhaust the gaseous carbon dioxide. It was found that some users had difficulty in moving the push button to a position to create the restricted orifice and release the gaseous carbon dioxide. As a result of the foregoing there exists a need for a simple, easy to assemble and efficient self-cooling system for a food or beverage which is easy to activate and less costly to manufacture.

SUMMARY OF THE INVENTION

In a food or beverage containing assembly comprising an outer container for receiving a food or beverage and having a top and a bottom, the bottom defining an opening therethrough, a heat exchange unit (HEU) including a metallic inner container having an opening and to be filled with liquid carbon dioxide (CO2) and adapted to be secured to the outer container in the opening, a valve means secured to said HEU for providing a restricted orifice having a dimension which, when activated, creates a dis-equilibrium to permit the liquid CO2 to pass directly from the liquid state to the gaseous state but at the same time to maintain the CO2 remaining in the HEU in its liquid state until it is fully exhausted, the improvement comprising a frangible member closing said opening in said HEU, said valve means including a pierce pin and a rotary activation member coupled to said pierce pin to move said pierce pin into contact with said frangible member to rupture the frangible member.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a phase diagram of carbon dioxide illustrating the pressure and temperature at which the CO2 is solid, liquid, gas and supercritical fluid;

FIG. 2 is a cross-sectional view of a container having a heat exchange unit constructed in accordance with the principles of the present invention;

FIG. 3 is a top perspective view of the container of the present invention utilizing the twist activation;

FIG. 4 is a partial cross-sectional view illustrating the various components of the activation system;

FIG. 5 is a perspective view of the heat exchange unit attachment adapter;

FIG. 6 is a cross-sectional view of the heat exchange unit attachment adapter taken above the lines 6-6 of FIG. 5;

FIG. 7 is a perspective view of the calibrated pierce plug of the present invention;

FIG. 8 is a side view of the calibrated pierce plug;

FIG. 9 is a cross-sectional view of the calibrated pierce plug taken above the lines 9-9 of FIG. 7;

FIG. 10 is a perspective view of the pierce pin;

FIG. 11 is a cross-sectional view of the pierce pin taken above the lines 11-11 of FIG. 10;

FIG. 12 is a perspective view of the twist base activator;

FIG. 13 is a perspective view of the ratchet attachment clamp ring;

FIG. 14 is a cross-sectional view illustrating the ratchet engagement with the base ring;

FIG. 15 is a cross-sectional view showing the vent path for the carbon dioxide gas;

FIG. 16 further illustrates the venting of the carbon dioxide gas to the atmosphere;

FIG. 17 is a plan view showing the punch profile of the bottom of the outer container;

FIG. 18 is a cross-sectional view of an alternative embodiment of a container having an HEU constructed in accordance with the principles of the present invention;

FIG. 19 is a cross-sectional view of the HEU assembly;

FIG. 20 is a cross-sectional view of the valve mechanism of FIG. 18; and

FIG. 21 is a cross-sectional view of another alternative embodiment of a container having an HEU constructed in accordance with the principles of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring now more particularly to FIG. 1, there is illustrated a phase diagram for carbon dioxide. As is therein illustrated, the carbon dioxide may have a solid phase, a liquid phase or a vapor or gas phase. In accordance with the principles of the present invention it is critical that the carbon dioxide be maintained in its liquid phase and prevented from passing into a solid phase where dry ice is formed during the time that the heat exchange unit is being utilized to lower the temperature of the food or beverage within the container. As is shown, the triple point on the phase diagram is the point at which the three states of matter (gas, liquid and solid) coexist. The critical point is the point on the phase diagram at which the substance, in this instance the carbon dioxide, is indistinguishable between liquid and gaseous states. The vaporization (or condensation) curve is the curve 10 on the phase diagram which represents the transition between the liquid and vapor or gaseous states. As is shown, the phase diagram plots pressure typically in atmospheres versus temperature, in this case, in degrees Celsius. The lines represent the combinations of pressures and temperatures at which two phases can exist in equilibrium. In other words, these lines define phase change points. In accordance with the principles of the present invention, the heat exchange unit is charged with carbon dioxide at a temperature and pressure such that the carbon dioxide is in its liquid state. The heat exchange unit is then sealed so that the liquid state is retained in equilibrium within the heat exchange unit until such a time as it is desired to cool the food or beverage within the container which surrounds the heat exchange unit. At that point, dis-equilibrium is created so that the liquid carbon dioxide is allowed to pass into the vapor or gaseous state but at the same time it is critical that the pressure within the heat exchange unit is maintained such that any carbon dioxide which still exists within the heat exchange unit is maintained in its liquid state. This is accomplished, as will be described in greater detail hereinbelow, by providing a path for the liquid carbon dioxide to pass from its liquid to its gaseous state and exhaust to the atmosphere by passing through a restricted orifice which has a dimension to create a pressure drop such that the pressure within the heat exchange unit is maintained so that the residual carbon dioxide which is contained within the heat exchange unit remains in its liquid state until such a time as all of the liquid carbon dioxide passes directly from its liquid state to its gaseous state and exhausts through the restricted orifice to the atmosphere, thereby completely exhausting the liquid carbon dioxide in the heat exchange unit and cooling the food or beverage in the container.

As indicated above and particularly with reference to the two previously filed PCT patent applications, systems were developed which did provide the desired dimension for the restricted orifice and did in fact function to cause the liquid carbon dioxide to pass directly from its liquid to its gaseous state and exhaust to the atmosphere and cool the food or beverage which was in contact with the heat exchange unit. It was, however, determined that the mechanism which was developed and is disclosed, was manufactured from machined metal parts and also, in one embodiment, the activation mechanism was a push button. As a result of the utilization of the machined metal parts, it was realized that the resulting mechanism was extremely expensive and would not be commercially feasible to produce and in the push button activation, as above noted, it was found that some individuals had a great deal of difficulty in depressing the button sufficiently to activate the restricted orifice and thus provide the ability of liquid carbon dioxide to pass from the liquid to the gaseous state and accomplish the desired cooling. As a result, Applicant redesigned the activating mechanism and the manner in which the restricted orifice was generated and at the same time eliminated the expensive machined parts thereby reducing the overall cost of the device so that it could be commercially developed. The present invention, therefore, is directed to the new structure which utilizes a twist base or rotary activator coupled to a pierce pin to move the pierce pin in such a manner that the frangible member is punctured to create the dis-equilibrium to cause the liquid carbon dioxide to pass directly into the gaseous state and accomplish the desired cooling. The redesign resulted in the structure including molded plastic parts and the only metal being the pierce pin and the heat exchange unit which will be more fully described below.

Referring now more specifically to FIGS. 2 and 3, there is shown the overall structure of one embodiment of the present invention including the twist base or rotary activator 20. As is shown in FIG. 2, the structure includes an outer container 12 and a heat exchange unit 14 attached to a heat exchange unit attachment adapter 16 which is affixed to the bottom 18 of the outer container 12. The twist base or rotary activator 20 may be rotated in a first direction in order to cause the pierce pin to move toward and rupture the heat exchange unit frangible member. As will be more fully described below, a mechanism is provided to prevent the twist base activator from being rotated in the opposite direction. In the preferred embodiment, the twist base activator is permitted to be rotated in a clockwise direction only as is indicated by the arrows 22 on the top of the twist base activator 20 in FIG. 3.

As has been described previously, the top 24 of the outer container 12 is closed and includes the typical pop top or lift tab to provide access to the contents 26 within the outer container 12 which may be a food or beverage and, in accordance with the preferred embodiment of the present invention, is a beverage which surrounds the outer surface of the heat exchange unit 14 so that the contents 26 may be cooled to a desired consumption temperature. The outer surface of the heat exchange unit in contact with the beverage is coated with a food grade coating to prevent metal pickup in the food or beverage as disclosed in U.S. Pat. No. 6,105,384 which is incorporated herein by this reference.

Referring now more particularly to FIG. 4, the assembly of the various component parts of this embodiment for attaching the HEU to the outer container is illustrated in greater detail. As is illustrated in FIG. 4, the HEU attachment adapter 16 is threadedly secured to the neck portion 28 of the heat exchange unit 14. The attachment adapter 16 is manufactured from an engineering plastic material which is reinforced with fiberglass. As one example, the adapter may be manufactured from a 50% fiberglass filled polyacrylamide or a fiberglass filled polyoxymethylene or an acrylonitrile butadiene styrene (ABS). The particular engineering material used must be food compatible. As is illustrated in FIG. 4, the attachment adapter has an upwardly extending neck portion which passes through an opening in the bottom 18 of the outer container 12.

By reference to FIGS. 5 and 6, the attachment adapter is illustrated in greater detail. As is therein shown, the adapter has a downwardly extending body portion 30 which includes threads 32 on the internal surface thereof for engaging the threads on the necked down portion of the heat exchange unit. The adapter includes an outwardly extending flange 34 which seats against the inner surface of the bottom 18 of the outer container 12. The adapter also includes an upwardly extending neck portion 36 which also has threads 38 formed on the exterior surface thereof as well as threads 40 formed on the inner surface thereof to receive a calibrated pierce plug which will be described more fully below. The adapter 16 also includes a pair of lugs 42 and 44 extending outwardly from the neck portion 36. The lugs 42 and 44 are utilized to hold the HEU in place and prevent it from turning when the twist base activator 20 is utilized as will be more fully described hereinbelow. The manner in which this occurs is illustrated by the beverage can punch profile which is shown in FIG. 17 to which reference is hereby made. As is therein shown, the bottom portion 18 of the outer container 12 has the opening 46 provided therein which receives the adapter 16 and a pair of slots 48 and 50 extending from the periphery of the opening 46 are also provided. The lugs 42 and 44 fit within the slots 48 and 50 thereby keeping the attachment adapter securely positioned within the bottom of the outer container 12. A ratchet attachment clamp ring 52 is seated over the neck 36 of the attachment adapter 16. The ratchet attachment clamp ring 52 is held in place by a nut 54 which is secured on the outer threads 38 of the neck portion 36 of the attachment adapter 16. Alternatively, a snap ring may be utilized in place of the nut 54 if such is desired. The ratchet attachment clamp ring 52 will be described in greater detail hereinbelow. As also illustrated in FIG. 4, a calibrated pierce plug 56 is threadably secured by the threads 40 on the internal surface of the neck portion 36 of the attachment adapter 16. A pierce pin 58 is secured internally of the calibrated pierce plug and is utilized when the twist base activator 20 is activated to puncture the frangible heat exchange unit member 60 to create the dis-equilibrium and to allow the liquid carbon dioxide contained within the heat exchange unit 14 to pass directly from the liquid to the gaseous state and to be exhausted to atmosphere as will be explained more fully hereinbelow.

The twist base activator 20 is also a molded plastic member formed from fiberglass filled engineering plastic material and includes a downwardly extending activating finger 62 which engages the calibrated pierce plug 56 in order to rotate it when the twist base activator 20 is rotated to cause the pierce plug to move downwardly and pierce the heat exchange unit frangible member 60.

Referring now more particularly to FIGS. 7, 8 and 9, the calibrated pierce plug is illustrated in greater detail. The calibrated pierce plug 56 is also constructed using a fiberglass filled engineering plastic material as above described. The pierce plug 56 defines a plurality of threads 64 on the outer surface of the body thereof which engage the threads 40 on the internal surface of the neck portion 36 of the attachment adapter 16 to thereby secure the pierce plug in place. The pierce plug 56 defines a hexagonal opening 66 in the top 68 thereof which engages with the finger 62 on the twist base activator 20 so as to move the calibrated pierce plug 56 downwardly as viewed in FIG. 4 to accomplish the piercing of the heat exchange unit frangible member 60. The body 70 of the pierce plug defines a slot 72 which extends along the entire length of the body 70 and extends through the threads 64 as illustrated. The slot 72 is utilized to provide a passage for the gaseous carbon dioxide to pass into the area where the restricted orifice is generated to allow passage of the gaseous carbon dioxide to the atmosphere as will be more fully described hereinbelow.

The outer surface 74 of the top portion 68 of the calibrated pierce plug 56 is a critical dimension and fits within a further critical region 76 of the attachment adapter as shown in FIG. 6. The combination of the outer surface 74 in conjunction with the inner surface 76 provides the desired dimension for the restricted orifice to be more fully discussed below.

The pierce pin 58 is shown in greater detail in FIGS. 10 and 11 to which reference is hereby made. As is illustrated, the pierce pin has a sharp point 78 which is utilized to puncture the heat exchange unit frangible member when the twist base activator 20 is rotated in the first direction. The pierce pin 58 has threads 80 formed on the external surface thereof which threads engage threads 82 formed on the internal surface of the pierce plug as shown in FIG. 9. Although the pierce pin is described as being threadably secured to the calibrated pierce plug, it should be understood that it could be press fitted into the calibrated pierce plug or formed as an overmolded unit where the pierce plug would be molded around the pierce pin if such is desired. As above noted, the pierce pin is the only element of the assembly that is formed from metal other than the heat exchange unit. As is shown particularly at 84, the pierce pin is formed with a hexagonal opening that is utilized to thread the pierce pin into place within the calibrated pierce plug 56.

Referring now more particularly to FIG. 12, the twist base activator 20 is illustrated in greater detail. The illustration in FIG. 12 is a perspective view showing the internal portion of the twist base activator 20 which cooperates with the ratchet attachment clamp ring and the calibrated pierce plug 56 to move the pierce pin 58 downwardly to puncture the heat exchange unit frangible member 60. The twist base activator 20 includes a downwardly directed outer rim 86 which, as will be more fully described below, is used to direct the gaseous carbon dioxide downwardly along the outer surface of the outer container 12. The twist base activator 20 includes a downwardly directed flange 88 which seats around the outer surface of the ratchet attachment clamp ring 52. An inwardly directed wedge-shaped lip extends from the bottom of the flange 88 and defines a shoulder 89 which seats against a surface 91 on the ratchet attachment clamp ring 52 as shown in FIG. 4 to hold the twist base activator 20 in place. When the components are assembled, the twist base activator 20 is placed in position and pushed downwardly. The flange 88 will move outwardly and the wedge-shaped lip will snap into place to secure the twist base activator 20. A plurality of stiffening ribs 90 extend between the outer surface 92 of the flange 88 and along the top surface and into engagement with the inner surface of the rim 86 merely to provide additional structural integrity to the twist base activator 20. The twist base activator 20 includes the downwardly extending activating finger 62 which includes an irregular surface 92 which cooperates with the opening 66 in the calibrated pierce plug to turn the calibrated pierce plug when the twist base activator 20 is rotated to cause the pierce pin to move downwardly and puncture the heat exchange unit frangible member 60. A plurality of ratchet teeth 94 extend completely around the actuating finger 62 and along the inner edge of the flange 88. The ratchet teeth cooperate with the ratchet attachment clamp ring as will be described below to allow the twist base activator 20 to rotate only in the clockwise direction and to prevent it from rotating in the counterclockwise direction. It should, however, be understood by those skilled in the art that if desired, the ratchet teeth and the clamp ring may be designed such as to cause the twist base activator to be rotated in the counterclockwise direction for activation and to prevent rotation in the clockwise direction should such be desired.

Referring now more particularly to FIG. 13, the ratchet attachment clamp ring 52 is illustrated in greater detail. The ratchet attachment clamp ring 52 includes an upwardly extending flange 96 which defines a ratchet leg 98 and a ratchet leg 100 which are situated 180° apart on the flange 96. The ratchet legs 98 and 100 cooperate with the ratchet teeth 94 to allow the twist base activator 20 to rotate only in the clockwise direction as above described. If an attempt is made to rotate the twist base activator 20 in a counterclockwise direction, the ratchet legs 98 and 100 will prevent such from occurring as a result of the ratchet teeth 94. As is illustrated, the ratchet attachment clamp ring includes an opening 102 which includes recesses 104 and 106. The recesses 104 and 106 cooperate with the lugs 42 and 44 on the attachment adapter 16 to retain the ratchet attachment clamp ring in position to function properly.

Now, by reference to FIG. 14, cooperation of the twist base activator 20 and the ratchet attachment clamp ring 52 is illustrated. As is therein shown, the ratchet attachment clamp ring 52 is in position such that the ratchet legs such as shown at 98 cooperate with the ratchet teeth 94 so that when the twist base activator 20 is rotated in a clockwise direction as shown by the arrow 108, the ratchet leg 98 will permit such to occur. If, however, an attempt is made to move the twist base activator 20 in the opposition direction, the ratchet leg 98 would engage the ratchet teeth 94 and prevent such movement.

Referring now more particularly to FIG. 15, there is illustrated the gaseous carbon dioxide vent path when utilizing the various elements of the activation system as above described. As is shown in FIG. 15, when the twist base activator 20 is rotated in a clockwise direction, the finger 62 will cause the pierce plug 56 to rotate and the threads 64 thereon will cooperate with the threads 40 on the attachment adaptor 16 to move the pierce pin 58 downwardly to rupture the heat exchange unit frangible member 60 creating dis-equilibrium allowing the liquid carbon dioxide to boil and to move from the liquid state directly into the gaseous state. The gaseous carbon dioxide would then pass as shown by the arrow 110 upwardly along the slot 72 in the calibrated pierce plug and would then pass by the restricted orifice 75 formed between the outer surface 74 of the calibrated pierce plug and the critical inner surface 76 of the neck 38 of the attachment adapter 16. The combination of those two surfaces provides the dimension of the restricted orifice which, in accordance with the presently preferred embodiment of the present invention, provides a 12 micron annulus opening allowing the gaseous carbon dioxide to pass through the restricted orifice and outwardly into the area underneath the twist base activator 20 as shown by the arrow 112. However, the 12 micron annulus creates a pressure drop such that any residual carbon dioxide in the HEU remains in the liquid state.

As shown in FIG. 16 to which reference is hereby made, once the gaseous carbon dioxide has passed through the restricted orifice 75, it then passes as shown by the arrows 114 through the opening 116 beneath the ratchet plug 98 underneath the rim edge of the flange 88 and outwardly along the bottom portion of the outer container 12 and downwardly along that surface as shown by the arrow 118. As a result of this passage of the gaseous carbon dioxide, not only is the cooling accomplished utilizing the heat exchange unit internally of the outer container, but also additional cooling is provided by the gaseous carbon dioxide passing along the outer surface of the outer container 12.

To provide a cost savings for the structure as described hereinabove, the heat exchange unit is manufactured from steel utilizing a draw and redraw process allowing a high speed manufacturing process and provides a heat exchange unit of a configuration and volume to receive approximately 90 grams of liquid carbon dioxide. In addition thereto, the heat exchange unit is filled with liquid carbon dioxide and the heat exchange unit frangible member is placed across the opening in the heat exchange unit and is sealed prior to the heat exchange unit being incorporated into the outer container 12. Such is done by placing the formed heat exchange unit in a carbon dioxide pressure atmosphere of the sufficient amount to create the liquid carbon dioxide. Once the heat exchange unit has then been totally filled with the 90 grams of carbon dioxide, the frangible member is placed across the opening of the heat exchange unit and sealed in place and then the pressure atmosphere is opened to atmosphere and the gassed heat exchange unit is removed. The frangible member 60 also provides the function of a burst disc. If the pressure in the HEU becomes excessive, the member 60 will rupture and allow the carbon dioxide to exhaust safely to atmosphere. Through utilization of this type of method for pregassing the heat exchange unit, the overall cost is reduced by about 60%.

To provide the desired restricted orifice as above described, the opening is defined as a H7 g6. The H7 refers to the opening dimension 76 in the neck 38 of the attachment adapter 16 and the g6 refers to a dimension of the outer surface 74 of the calibrated pierce plug. The combination of those two dimensions will provide the annulus of 12 microns through which the gaseous carbon dioxide must pass to then ultimately be exhausted to the atmosphere as above described.

Referring now more particularly to FIG. 18, there is illustrated an alternative embodiment of a beverage container having a heat exchange unit utilizing a twist top activation system which is a simplified version of that described above. As is shown in FIG. 18, the beverage container 120 has the heat exchange unit 122 secured to the bottom 124 of the container 120. A support collar 126 is positioned over the neck 128 of the HEU and has one end thereof seated against the HEU and the other end thereof seated against the bottom of the container and the attachment housing 130 is threadably secured to the neck 128 of the HEU 122 and in so doing secures the HEU to the bottom 124 of the outer container 120.

The assembly of the HEU is shown in greater detail in FIG. 19 to which reference is hereby made. As is therein illustrated, the HEU 122 includes threads 132 on the outer surface thereof and additional threads 134 on the interior thereof. An adapter 136 is threadably secured to the threads 134 on the interior of the neck of the HEU 122. The adapter 136 is hollow as shown and defines a shoulder 138 which receives a spring 140. A valve stem 142 is inserted into the hollow interior of the adapter 136. The valve stem 142 defines an inwardly directed lip 144 at the lower end thereof. The lip 144 snaps into place and seats within a groove 146 defined in the frangible member or burst disk holder 148. The frangible member or burst disk 150 is a frangible member and is seated within the holder 148 and is secured in place by a grub screw 152. A polytetrafluoroethylene (PTFE) washer 154 is seated on top of the burst disk holder 148 and seats against the bottom of the adapter 136 to provide a seal to retain the liquid carbon dioxide which is housed internally of the HEU 122 as will be described more fully below. The grub screw 152 defines an opening 156 therein. It will be recognized by those skilled in the art that the burst disk 150 is continuously exposed to the pressure of the liquid carbon dioxide contained within the HEU 122 and if the pressure therein exceeds a predetermined amount, the burst disk 150 will rupture and the liquid carbon dioxide will then commence boiling and will exhaust through the opening 156 and outwardly into the atmosphere. The opening 156 is used to throttle the gas to some extent to protect the components contained within the valve mechanism upstream of the burst disk 150.

To fill the HEU 122 with liquid carbon dioxide, the assembled HEU as shown in FIG. 19 is contacted by the liquid carbon dioxide filling head which pushes the valve stem 142 downwardly as viewed in FIG. 19 causing the burst disk holder 148 to move downwardly breaking the seal defined by the PTFE washer 154 so that liquid carbon dioxide can then enter the HEU 122. When the desired amount of liquid carbon dioxide is contained within the HEU 122, the filling head is removed and the spring 140 will move the valve stem upwardly allowing the seal defined by the washer 154 to engage between the top of the burst disk holder 148 and the bottom of the adapter 146 to again provide a seal and to maintain that seal so that the liquid carbon dioxide is retained in equilibrium internally of the HEU 122. Once this is accomplished, the filled HEU will then be assembled with the remainder of the valve mechanism as illustrated in FIG. 18.

By referring now more particularly to FIG. 20, the details of the valve mechanism are illustrated in greater detail. As is shown in FIG. 20, a pierce pin 160 is contained within a pierce plug 162 as above described. The pierce pin 160 is metal and has a sharp point 164. The pierce plug 162 defines a plurality of drive splines therein which are engaged by the downwardly directed finger 164 on the twist activator 166. The pierce plug 162 is carried by the attachment housing 168 in such a manner that when the twist activator 166 is rotated in a single direction such as clockwise as hereinabove described, the pierce plug 162 drives the pierce pin 160 downwardly so that the point 164 contacts and ruptures the burst disk 150 allowing the liquid carbon dioxide contained internally of the HEU 122 go into disequilibrium, boil and pass from the liquid state directly to the gaseous state and move through the opening 156 upwardly around the pierce pin internally of the valve stem 142 and outwardly through the slot 72 (FIG. 8) which is formed in the threads of the pierce plug 162 to engage the lower surface of the twist activator 166 and pass outwardly and downwardly as above described. A restricted orifice is disposed in the gas flow path as above described and is dimensioned to provide the pressure drop to maintain the residual CO2 in the HEU in the liquid state until all of it passes directly into the gaseous state and exhausts as above described. It can be seen from the illustration of FIG. 20 that the structure of the valve mechanism as contained in this embodiment is simplified from that shown in the embodiment described hereinabove, thus allowing greater ease of assembly and provides a less expensive valve mechanism. For example, the attachment housing 168 is a single molded plastic member replacing the attachment adaptor 16, ratchet attachment clamp ring 52 and the nut 54 of the embodiment illustrated in FIG. 4.

A support collar 126 carries O-rings 170 and 172. The O-ring 170 prevents the beverage contained within the outer container 120 from contacting the outer surface of the HEU which does not have a protective coating thereon. The O-ring 172 provides a seal to prevent the beverage contained within the outer container 120 from leaving the interior of the container 120.

By referring now to FIG. 21, there is illustrated yet a further embodiment of a twist activated HEU constructed in accordance with the principles of the present invention. The structure as shown in FIG. 21 has a different adapter 174 which is designed to accommodate a different type of HEU from that shown in FIG. 20. As is also shown in FIG. 21, the HEU support collar 176 is slightly different in structure from that shown in FIG. 20. In all other respects the structure shown in FIG. 21 is identical to that shown in FIG. 20 and functions in the same manner and, therefore, the description of FIG. 20 otherwise is incorporated herein with respect to FIG. 21.

There has thus been described a modification of a heat exchange unit which has been designed to be activated by a twisting motion as opposed to utilizing a pushbutton type of activation as previously described and which utilizes molded plastic parts as opposed to machined metal parts as also previously described to substantially reduce the manufacturing cost of the system. 

1. In a self-chilling food or beverage container (12) having a heat exchange unit (14) secured to an opening in the bottom thereof and extending into contact with the food or beverage and having a valve mechanism (140-142) for inserting liquid carbon dioxide into the heat exchange unit through an opening therein, the improvement characterized by a frangible member (60-150) closing the opening in the heat exchange unit; the valve mechanism including a pierce pin system (56, 58-160, 162) disposed adjacent said frangible member; a rotary activation member (20-166) coupled to said pierce pin system adapted to rotate only in one direction and, when so rotated, advances said pierce pin into engagement with said frangible member to pierce it to allow liquid carbon dioxide to pass from the liquid state to the gaseous state and exhaust along a flow path; and a restricted orifice (75), disposed in said flow path and having a dimension to create a pressure drop that retains any residual carbon dioxide in the heat exchange unit in the liquid state.
 2. The improvement in a self-chilling food or beverage container as defined in claim 1 wherein the pierce pin system includes a pierce plug (56-162) and a pierce pin (58-160) carried by said pierce plug and said rotary activation member (70-166) engages said pierce plug to rotate said pierce plug to advance said pierce pin into engagement with said frangible member.
 3. The improvement in a self-chilling food or beverage container as defined in claim 2 wherein said pierce plug defines an opening (66) therein and said rotary activation member includes a finger (62) which extends into said opening in said pierce plug to rotate said pierce plug.
 4. The improvement in a self-chilling food or beverage container as defined in claim 3 wherein an outer surface (74) of the pierce plug cooperates with a region (76) of an attachment adapter (16) to define said restricted orifice (75).
 5. The improvement in a self-chilling food or beverage container as defined in claim 1 wherein said frangible member functions as a burst disk which is in constant contact with the liquid CO2 and will rupture when pressure within the HEU reaches a predetermined level.
 6. The improvement in a self-chilling food or beverage container as defined in claim 1 wherein said rotary activation member includes ratchet teeth (94) which cooperate with ratchet legs (98-100) to prevent said rotary activation member from rotating in a direction other than said one direction.
 7. The improvement in a self-chilling food or beverage container as defined in claim 1 wherein said rotary activation member includes a downwardly directed outer rim (86) which directs the exhausting CO2 gas flow downwardly along the outer surface of the container (12).
 8. The improvement in a self-chilling food or beverage container as defined in claim 1 wherein said heat exchange unit includes a neck portion (28-128) having threads (132) on the outer surface thereof and which further includes an adapter (16-136) threadably secured to said threads on the neck of the HEU to secure the HEU to the bottom of the container.
 9. The improvement in a self-chilling food or beverage container as defined in claim 8 wherein the adapter is manufactured from an engineering plastic material comprising a fiberglass filled polyacrylamide or a fiberglass fitted polyoxymethylene or a acrylonitrile butadiene styrene (ABS).
 10. The improvement in a self-chilling food or beverage container as defined in claim 8 wherein said rotary activation member (20-166) includes a downwardly directed flange (88) having an inwardly directed wedge-shaped lip which secures the rotary activation member to the adapter.
 11. The improvement in a self-chilling food or beverage container as defined in claim 8 which further includes a frangible member holder and a grub screw (152) which secures the frangible member in place in the holder.
 12. The improvement in a self-chilling food or beverage container as defined in claim 11 which further includes a sealing member seated between the frangible member holder and the bottom of the adapter (136) to maintain the liquid carbon dioxide in the HEU in an equilibrium state.
 13. The improvement in a self-chilling food or beverage container as defined in claim 12 wherein the adapter is hollow and further includes a valve stem (142) disposed in the hollow interior of the adapter and a spring urging the valve stem to a position to urge the frangible member into a sealing position, the valve stem being movable against the force of the spring to move the frangible member holder away from the bottom of the adapter to allow liquid carbon dioxide to be inserted into the HEU.
 14. The improvement in a self-chilling food or beverage container as defined in claim 11 wherein said grub screw includes an opening therein through which the pressure in the HEU is communicated to the frangible member, the opening in the grub screw being dimensioned to throttle the pressure of released gaseous carbon dioxide in the event the frangible member ruptures as a result of increased pressure in the HEU.
 15. The improvement in a self-chilling food or beverage container as defined in claim 8 which further includes a HEU support collar (126) surrounding the neck portion (128) of the HEU and seated against the HEU at one end thereof and against the bottom of the container at the other end thereof for securing the HEU to the container. 